Recovery of β-lactamase producing bacteria in pediatric infections

The presence of β-lactamase producing bacteria (βLPB) was investigated in specimens obtained from 1469 children who presented with infections of the skin and soft tissue (648), upper respiratory tract (514), pulmonary sites (137), surgical sites (113), and other (57). Of 4989 bacterial isolates recovered, 910 (18%) were βLPB, 492 (54%) aerobes, and 418 (46%) anaerobes. The βLPB were recovered in 751 (51%) of the children. The most frequently recovered βLPB was Staphylococcus aureus, which was recovered in 356 (47%) patients. Most isolates were recovered from patients with skin and soft-tissue infections (68% of patients), upper respiratory tract infections (49%), and pulmonary infections (35%). Bacteroides fragilis group was isolated in 35% of patients with βLPB, mostly from surgical infections (98% of patients), pulmonary infections (36%), skin and soft-tissue infections (25%), and upper respiratory tract infections (20%). Twenty-five percent of the Bacteroides melaninogenicus group produced β-lactamase. These organisms were recovered in 15% of patients with βLPB. They were recovered in upper respiratory tract infections (38% of patients), pulmonary infections (22%), and skin and soft-tissue infections (7%). Other βLPB were Pseudomonas aeruginosa (8% of total patients with βLPB), Escherichia coli (4%), Bacteroides oralis (3%), Klebsiella pneumoniae (3%), Haemophilus influenzae (2%), Proteus (1%), and Branhamella catarrhalis (1%). The role of βLPB in the failure of penicillin to eradicate many of the infections is discussed.